Pavement cutting apparatus



Feb. 19, 1957 W. H. LEWIS PAVEMENT CUTTING APPARATUS Filed April 17,1953 9 Sheets-Sheet l Feb. 19, 1957 w. H. LEWIS 2,782,017

PAVEMENT CUTTING APPARATUS Filed April 17, 1955 9 Sheets-Sheet 2 -n cexcalllllii ngwsmn Il! INVENToR. WML/nM A. sw/.s

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Feb. 19, 1957 w. H. I Ewls 2,782,017

PAVEMENT CUTTING APPARATUS Filed April 17, 1953 9 Sheets-Sheet 3 IN V ENTGR.

Feb. 19, 1957 w. H. LEWIS PAVEMENT CUTTING APPARATUS Filed April 17,1953 9 Sheets-Sheet 4 .SAEM www.

Feb. 19, 1957 wfH. I Ewls 2,782,017

PAVEMENT CUTTING APPARATUS Filed April 17, 1953 9 Sheets-Sheet 5 lll/lllFeb. 19, 1957 w. H. I Ewis 2,782,017

PAVEMENT CUTTING APPARATUS Filed April 17, 1953 9 Sheets-Sheet 6 IN V ENTOR. WHL/4M A. Lew/s w. H. LEWIS 2,782,017

PAVEMENT CUTTING APPARATUS Feb. 19, 1957 9 Sheets-Sheet 7 Filed April17, 1953 Feb. 19, 1957 w. H. I Ewls PAVEMENT CUTTING APPARATUS 9Sheets-Sheet 8 Filed April 1'7, 1953 Feb. 19, 1957 w. H. LEWIS 2,782,017

PAVEMENT CUTTING APPARATUS Filed April 17, 195s 9 Sheets-Sheet 9 x ylsoa 256, Wel-2? JNVENTOR. WML/0M ll. cw/.s

ha@ @fw PAVEMENT CUTTING APPARATUS William H. Lewis, Arcadia, Calif.,assigner, by messie assignments, to Joint Saw Company, Arcadia, Calif.,a corporation of California Application April 17, 1953, Serial No.349,418

15 Claims. (Cl. 262-20) The present invention relates generally topavement cutting apparatus, and more particularly to apparatus forcutting slots or kerfs in a paved surface.

In the construction of paved roads, driveways, airport runways, and thelike, it is customary after laying the pavement to tamp transverselyextending separator strips at longitudinally spaced points in the wetpaving material. The purpose of these separator strips is to defineweakened plane joints in the paving material; contraction of the pavingmaterial as it hardens causing it to crack at each of the weakened planejoints. If such weakened plane joints were not provided, the pavementwould be damaged by the uncontrolled cracking which would otherwiseoccur during its contraction.

The use of these separator strips has met with considerabledissatisfaction because the pavement finishing machine which follows thetamping equipment used to insert the separator strips in the pavementoften deforms these strips, producing a joint which weaves transverselyacross the pavement. Additionally, should the separator strip be tampedtoo low, the passage of the finisher over these strips may inducespalling of the upper portion of the pavement with a resultant raggedjoint.

ln order to avoid the disadvantages involved in the use of suchseparator strips it has been proposed to machine saw or cut the weakenedplane joints. Such machine sawing has heretofore been carried outprimarily by means of comparatively small hand operated machinesutilizing one or two power-driven cuttings discs and adapted to be movedtransversely across the highway whereby their cutting discs may saw thekerfs which deiine the weakened plane joints. Although these machinesare generally satisfactory for use in forming the kerfs defining theweakened plane joints ot a short section of roadway, they proveunsatisfactory when used to form the weakened plane joints in acomparatively long roadway section. This is true because of thecomparatively short period of time within which it is necessary that theweakened plane joints be formed. Such joints cannot be formed in regularcontinuity as is true in the case of tamping the separator strips.Instead, it is necessary to first form a series of control joints. Thesecontrol joints insure that initial hardening and consequent contractionof the pavement does not crack the pavement surface. Ordinarily these.control joints are formed at approximately sixty-foot intervals.Thereafter, joints may be formed at approximately thirty-foot intervalsand then at approximately litteen-foot intervals. The forming' of theseweakened plane joints is further complicated by the fact that should thecutting operations commence before the pavement has suiiicientlyhardened, the cutter disc will pull pebbles out of the pavement insteadof cutting through them, leaving the sides of the joints badly spalled.If, however, the pavement is cut after it has hardened to an excessivedegree, the rate at which the cutting discs are able to move through thepavement is seriously reduced and their service life is considerablyshortened.

Under these circumstances the disadvantages of utiliznited States PatentICC ing heretofore proposed hand operated pavement cutting machines toform the kerfs defining the weakened plane joints in a long section ofroadway will be readily observed. Unless a large number of such machinesare provided, it is diflicult to form even the sixty-foot spaced controljoints before the pavement contracts to a point where it is damaged, andassuming that a comparatively large number of these machines should beemployed, it would still be diicult to form the thirty and fifteen-footspaced joints before the pavement has hardened to such a degree that thecutting rate and service life of the cutter disc is seriously reduced.lf a suflicient number of these small machines are provided that thekerfs can besawed within the required period of time, their combined ex?pense to purchase, maintain and operate becomes excessive.

It is a major object of the present invention to provide a singlemachine for cutting weakened plane joints which may be used in place ofa large number of the heretofore proposed small machines.

Another object is to provide a novel pavement cutting apparatus having aframe which is supported for longitudinal movement along an elongatestrip of pavement, and a plurality of transversely spaced cutter discsoperatively connected to the frame in order that they may be movedtransversely across the paved strip so as to form a transverselyextending kerf therein at longitudinally spaced points along its length.

lt is a further object of the invention to provide pavement cuttingapparatus having a plurality of transversely spaced cutter discs whichare moved concurrently across a paved strip so as to saw a transverselyextending kerf therein.

It is another object to provide pavement cutting apparatus having novelmeans for supplying its cutter discs with coolant in order that aminimum quantity of coolant will be required for cutting a maximumnumber of kerfs.

A further object of the invention is to provide pavement cuttingapparatus which will not damage the surface of the pavement whereon itis operated.

An additional object is to provide pavement cutting apparatus utilizingcutter discs driven by an internal combustion engine, and having novelmeans for conserving the amount of fuel required by said engine.

A more particular object of the present invention is to provide novelcutting apparatus which is especially adapted to form kerfs extendingdiagonally across a paved strip relative to the side edges thereof.

It is another object to provide pavement cutting apparatus capable ofcutting a large number of weakened plane joints in a roadway in aminimum amount of time. This permits the road building job to becompleted without annoying and costly delays.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description of a preferred,and of an alternate embodiment thereof, when taken in conjunction withthe appended drawings wherein:

Figure l is a general perspective View of a preferred form of pavementcutting apparatus embodying the present invention.

IFigure 2 is a rear view of said apparatus;

Figure 3 is a fragmentary, enlarged View of a cutter disc mounted bysaid apparatus;

Figure 4 is a vertical sectional view taken along line 4 4 of Figure 3;

lFigure 5 is a rear view of said apparatus during a pavement cuttingoperation;

'Figure 6 is 'a side view of said apparatus;

'Figure 7 is an enlarged top plan view taken from a point indicated bythe numeral 7 in Figure 6;

Figure 8 is a vertical sectional View taken along line 8-8 of Figure 6;

Figure 9 is an enlarged vertical sectional view taken along line 99 ofFigure 8;

Figure l is an enlarged vertical sectional view taken along line 10-10of Figure 8;

Figure 1l is a vertical sectional view taken on line llt-11 of Figure 7;

Figure 12 is a fragmentary enlarged vertical sectional View disclosing adetail of certain parts shown in Figure ll, but taken when said partsare 4disposed in different posi-tions;

`Figure 13 -is an enlarged vertical sectional View similar to Figure 12but showing said parts in yet another position;

Figure 14 is a fragmentary top plan View taken from the point indicatedin Figure 12;

Figure l5 is a schematic view of the hydraulic system utilized with thepreferred form of apparatus;

Figure 16 is a top plan view showing the mode of operation of `thepreferred form of apparatus;

iFigure 17 is a side elevationalview of an alternate form of pavementcutting apparatus embodying the present invention;

`Figure 18 is a side elevational view similar to Figure 17 but showingsaid apparatus` engaged in a pavement cutting operation;

Figure 19 is a vertical sectional view taken along lines 19-19 of Figure18;

Figure 20 is an enlarged horizontal sectional View taken on line 20-20of Figure 19;

Figure 21 is a fragmentary top plan view taken from the point indicatedin Figure 17;

Figure 22 is a fragmentary enlarged vertical sectional View taken online 2v2-22 of Figure 17;

Figure 23 is a vertical sectional view taken on line 23-23 of Figure 23;and

Figure 24 is a figure showing a cross section of the structure of Figure19 taken Ito the right of element 310 and looking toward element 310.

General arrangement of the apparatus shown in Figures 1 through 16Referring to the drawings, and particularly to Figures l Ithrough 6thereof, the preferred embodiment of the present invention broadlycomprises a frame F having wheels W supporting it for longitudinalmovement along a paved strip 28; a vcarriage C rotatably mounting aplurality of transversely spaced cutter discs 30, which discs arenormally supported above the surface of the paved strip 28 as shown inFigures 1, 2, and` 6; and poweractuated means H for effecting relativevertical movement between the frame F and 4the carriage C, The carriageC mounts auxiliary wheels 32 and 33 having their axes -of rotationdisposed at approximately right angles to the 'axes of rotation of thewheels W. In operation, `the frame F is moved along the paved strip 28in a longitudinal direction, stopping, at longitudinally spaced pointsthereon where a slot or kerf K is to be sawed therein. When thelongitudinal movement of the frame has been halted, the power-actuatedmeans H moves the carriage C downwardly until the auxiliary wheels 32and 33 thereof engage the surface of the strip. During such downwardmovement of the carriage the cutter discs will be brought intoengagement. with the paving strip prior to the time the `auxiliarywheels engage the strip. Further downward movement after the cutterdiscs have so engaged the paved stripwill cause them to be forceddownwardly into the pavement material of which the strip is composed.After the auxiliary wheels have been engaged wit-h the `paved strip 23,further relative vertical movement between the frame F and the carriageC causes the frame to be moved. upwardly so that itsrwheels W are liftedfreef. of. the surface of the paved strip. The entire unitcomprisinggthev frame and the carriage is then caused to movetransversely across vthe paved strip by power-operated means, generallydesignated 34, drivingly connected to the auxiliary wheels 32. Duringsuch transverse movement a transversely extending kerf will be cut inthe paved strip by the cutter discs 30.

The frame F More particularly, the frame F will preferably comprise apair of side elements 36 rigidly interconnected by lmeans of transversespacers 38, which elements and spacers may be channel-shaped incross-section. Connected `to the forward portion of the side elements 36is a downwardly extending `subframe 40. The front end of this subframe40 mounts the front axle 42, which axle rotatably supports the `frontwheels 44. These wheels may be of the conventional lautomotivepneumatic-'tired type. The front axle 42 is seen to be divided by atransmission 46, to the rear of which is disposed a gear box `L18. Fromthe rear of the gear box 48 extends a shaft (not shown) which is rigidlyconnected to Va pair of pulleys 52. These pulleys 52 are belt-driven bya smaller pair of pulleys 54; a pair of belts 56 being utilized toconnect the pulleys 52 and S4. The pulleys 54 are rigidly Secured tolthe front end of a drive shaft S8, which drive shaft is driven by powermeans such as an air-cooled internal combustion engine 60. A universaljoint connection 62 is interposed between the drive shaft 64 of theengine 60 and the drive shaft 58. With this arrangement, motive powerfrom the engine may be ltransferred to the front wheels 44 so as toeffect either forward or rearward motion of the frame F. The gear box 4Sprovides several speeds both in a forward and a rearward direction. Aclutch in the form of a bearing element 61 wherein is journaled thefront of the drive shaft 58 may be pivotally mounted to the frame by alever 62a. With this arrangement the tension of the belts 56 may bevaried so as to vary the amount of power transmitted thereby.

The rear portion of the frame side elements 36 extend inwardly and arejoined together at their ends. An `operators platform 66 is supportedupon this rear portion. At the junction of the frame elements 36 thereis rigidly mounted an upstanding tubular column 68. This column 68rcoaxially mounts a post 70, the bottom portion of which post is rigidlysecured to the midportion of rear axle 72. A pair `of wheels 74 aremounted at opposite ends of the rear axle. The post is adapted to berotated by means of a conventional steering wheel assembly 76 mounted at`the top of the column 68 whereby the rear wheels 74 may be steered. Anoperators seat 78 is supported over the platform 66 by means of aninclined support bar 30; the seat being disposed in such ya positionthat an operator seated thereon will have easy access to the steeringwheel 76, as well as other controls to be described hereinafter.

The carriage Referring now to Figures 4, 8, 9, and 10, the carriage Cwill preferably include a hollow elongated boom 84 of rectangularvertical cross-section. The cutter discs 30 may be of any type suitablefor cutting concrete, asphalt, or the like, and they are each rigidlysecured to the rear of a shaft 86. The shafts 86 are each rotatablyjournaled within. strap-type bearings 88 rigidly secured to theunderside of the boom 84. The front end of each shaft 86 rigidly mountsa pair of pulleys 90, The pulleys 90 are driven by internal combustionengines 92 and 94; the engine 92 driving the pulleys located on its sideof the carriage, and the engine 94 driving the pulleys located on` theopposite side of the carriage. To this end belts 96 connect the pulleys90 with pulleys 9S, the latter pulleys being keyed to the shafts of theengines 92 and 94. The boomV 84 may be connected to the frame F by meansof a pair of upstanding columns irigidly mounted as by welding at theirlower portions to the boom, 'which columns are slidably disposed withina pair of tubes 102 for axial movement with respect thereto. The tubes102 are rigidly secured as by welding at their lower portions to theside elements 36 of the frame F. The upper portion of the tubes 102 arerigidly connected by means of a horizontal cross-bar 104. With thisarrangement, the columns 100 may slide axially within the tubes 102whereby the carriage is vertically reciprocable relative to the frame.The height to which the carriage rises may be controlled by adjustmentbolts 105.

With further reference to Figures 8, 9, and l0, only one of the pairs ofthe auxiliary wheels 32 and 33 are power driven, which pair 32 appearsat the left of the carriage in Figure 8 and are shown in detail inFigure 9. The power driven wheels 32 are each keyed to opposite ends ofa horizontal shaft 120. A pair of pulleys 122 are also keyed to theshaft 120. The shaft 120 is concentrically disposed within a cylinder124 for rotation relative thereto, which cylinder is mounted withinslots 126 formed at the front and the rear of the boom 84. The oppositeends of the cylinder 124 rigidly mount depending stud bolts 128, whichbolts extend through bores formed in the opposite ends of a cross-piece130. rIhe cross-piece 150 is rigidly secured, as by welding, to theunderside of the boom 84. The stud bolts 128 are secured to thecross-piece 130 by means of adjusting nuts 132. The wheels 32 areadapted to be driven by the engine 92 in a manner to be fully set forthhereinafter.

Referring now to Figure 10, the other pair of auxiliary wheels 33 areindependently rotatably mounted at the opposite ends of a horizontalshaft 134, which shaft is disposed within slots 136 formed in the boom84. The opposite sides of .the shaft 136 rigidly mount a pair ofdownwardly extending stud bolts 137 similar to those shown in Figure 9,which stud bolts are secured by means of adjusting nuts 139 to across-piece 138 welded to the underside or" the boom 84. It will beapparent that adjustment of .the depth of the kerf K may be accomplishedby manipulation of the adjusting nuts 132 and 139.

Preferably, the auxiliary wheels will mount tires of solid rubber.

Arrangement for supplying coolant t0 the cutter discs Referring now toFigures 3 and 4, it is desirable that a coolant such as water besupplied to the cutter discs 30 during the actual pavement cuttingOperation. To this end, each cutter disc may be provided with a nozzle146. These nozzles 146 are shown mounted by an L- shaped pipe 145 havingits upper end secured within a collar 150, as by a bolt 152. The upperend of each pipe 143 is connected to one end of a hose 154. The oppositeend of this hose 154 is connected .to a control valve 156. The oppositeend of the control valve 156 is attached to a common conduit 158 whichis in communication with each of the other control valves 156. Thecommon conduit 158 is connectable with a source of water by means of afitting 161). This source of water may conveniently comprise atruck-mounted tank (not shown), which truck may be driven alongside thepaved strip 28 in conjunction with the described apparatus. Alternately,a suitable tank may be mounted upon the frame or .the carriage of thedescribed apparatus, or may be pulled behind said apparatus as it movesalong the paved strip 2S. The flow of water through each control valve156 is controlled by a horizontal rod 162, slidably mounted upon therear of the carriage. This rod 162 is pivotally connected to levers164:1 extending from each of the control valves 156. With thisarrangment, horizontal movement of the rod 162 in one direction willopen all of the control valves 156, while movement of this rod in theopposite direction will close all of these control valves.

It should be particularlynoted that ythe present invention providesnovel means for cutting oi the flow o coolant to the cutting discs 30when the latter are not actually engaged with the paved strip 28. Thisis an important feature, inasmuch as it avoids possible dilution of thefreshly laid pavement and it reduces the amount of coolant which must betransported along the paved strip. As shown in Figures 2 and 5, thisnovel means includes a rigid upstanding cam rod 164 secured at its lowerend `to the horizontal rod 162 as by welding. The cam rod 164 is formedat its intermediate portion with an olset section 166. During verticalmovement of the carriage relative to the frame, the cam rod 164reciprocates vertically relative to an encompassing lug 168er shownrigidly secured to one side of the operators platform 66. As clearlyshown in Figure 2, when the carriage C is in its elevated position thehorizontal rod 162 is biased to the left by a helical tension spring170. At this time the control-valves 156 will be closed. When thecarriage is moved downwardly, however, the offset vsection 166 of thecam rod will engage the sides of the The power-actuated means HReferring now to Figures 1 and 8, the preferred form of power-actuatedmeans H for effecting relative vertical movement between the frame F andthe carriage C iucludes a vertical rod 172 pivotally secured at itsupper end to the mid-portion of the cross-bar 104 and rigidly connectedat its lower end to a piston 173, and a hydraulic cylinder 174 whereinthe piston 173 is reciprocally disposed. 111e lower end of this cylinder174 may be pivotally secured to the center of the carriage boom 84. Thehydraulic cylinder 174 is adapted to receive hydraulic fluid underpressure so as to effect vertical reciprocation of the piston 173 andhence of the rod 172 respective to the cylinder 174. This reciprocatonwill cause concurrent relative vertical movement between the frame andthe carriage. The cylinder 174 is adapted to receive hydraulic iluidunder pressure from a pump 176 shown in Figure 8 as being mounted on theright side of the boom 84. This pump 176 is belt-driven from theinternal combusion engine 94; the shaft of the pump being keyed to apulley 178 which is aligned with a complementary pulley 180 keyed to theshaft of the engine. Pulleys 1.78 and 18) are connected by a belt 182.The pump 176 is supplied with hydraulic fluid from a suitable reservoir184 shown mounted within the boom S4 underneath the pump, the reservoirbeing connected to the pump intake by a conduit 156. The pump outlet isconnected to another conduit 188.

With particular reference to Figure 15, in the preferred form ofhydraulic system, the outlet conduit 188 is connected with a maincontroller valve 190 having an operating handle 191. From the maincontroller valve a conduit 192 extends to the bottom of the cylinder174, a return conduit 194 extends to the reservoir 184, another conduit196 extends to one side of a cam-operated throttling valve 198. Aconduit 202 connects the opposite side of the throttling valve 193 withthe top of the cylinder 174. The conduits 196 and 202 are interconnectedby an orice valve 204 and a one-way check valve 206, A restrictor valve208 is interposed between the lower end of cylinder 174 and the conduit192, and a similar restrictor valve 210 is interposed between the upperend of this ycylinder and the conduit 202. These restrictor valves areso constructed that they permit unhampered flow of uid into thecylinder, but ow out of 7 the cylinder is restricted to a desired rate.A pressure relief valve 212 is disposed between the pump outlet and thereservoir 184. The throttling valve 198 and the main controller valve190rnay be connected by a bleed line 200. The operation of thishydraulic system is fully set forth hereinafter.

The arrangement for driving auxiliary wheels 32 As mentionedhereinbefore with reference to Figure 9, the shaft 120 mounting theauxiliary wheels 32 is keyed to a pair of pulleys 122. Referring againto Figure 8, it will be seen that these pulleys 122 are conncctcd bybelts 212 to a pair of pulleys 214 keyed to the outlet shaft 216 of aclutch member generally designated 218. The tension of belts 212 may becontrolled by idler pulleys 213. The input shaft 220 of this clutchmember 218 rigidly mounts a pair of pulleys 222 which are connected bybelts 224 to a pair of pulleys 226 keyed to the shaft of the internalcombusion engine 92. The clutch member 21S is adapted to control theamount of power transmitted to and the rotational speed of the pulleys214, and hence of the auxiliary wheels 32. This clutch member 218 isadjustable manuallyby a lever 228.

Explanation of Figures I] through 14 lt should be particularly observedthat the present invention contemplates novel means for controlling thevertical movement of the carriage C relative to the frame F. Included insuch means is the cam-operated throttling valve 19S referred tohereinbefore in connection with the description of Figure 15. This valveis so designed that hydraulic fluid is free to pass through it betweenconduits 1.96 and 202 when its wheel 230 is in the extended positionshown in Figures ll and 15. When thc wheel 220 is retracted inwardlyrelative to the main body of the valve, however, llow between conduits196 and 202 is cut off. When the wheel 236 `is disposed intermcdiatelyof its fully extended position and fully retracted position, thequantity of fluid passing therethrough will vary in relation to itsaxial position relative to the main body of the valve.

The throttling valve 19S is rigidly mounted to the upper end of anupright post 232 secured at its lower end to the carriage boom 84. Thewheel 230 is adapted to be moved relative to the main body of the valveby contact with a cam plate 234; carried by the frame F. This cam plate234 is attached to a vertically extending elongated adjustment member236 rigidly connected as by welding to one of the frame elements 36. Tothis end, t e adjustment member 236 is formed with a slot 238. Verticaladjustment of the cam plato relative to the member .236 is effected bymeans of the bolt and nut combinations 240. The upper and lower ends ofthe cam plate 234 are seen to be beveled. It will be apparent that uponrelative vertical movement between the frame and carriage, the cam wheel236 will be moved between its extended and retracted positions bycontact with the upper and lower ends of the cam plate 234.

General operation of the apparatus shown in Figures through 16 Inoperation, the apparatus is driven along the paved strip 2S with bothengines 92 and 94 in operation and with the carriage C in a raisedpositionV to the point where the first kerf is to be formed. Normally,referring to Figure 16, the cutting operation takes place from right toleft in plan View. Hence, the cutter disc located at the right end ofthe carriage must be spotted over the right side of the paved strip atthe exact point where the kerf is to be formed with the carriagedisposed at right angles to the strip. As an aid in such spotting, apointer 245 may be mounted at the right portion of the carriage, thefreefend of which pointer is adapted to be aligned with the right side`248 of the paved strip.` Prefv erably, thispointer 246 willbe`adjustable as to its effec- 8 tive length and as Vto thc angle it makeswith the carriage.

After the apparatus has been properly spotted, with the cutter discs 30rotating, the operator may move thc operating handle 191 of the maincontroller valve 190 so as to admit hydraulic fluid into the lower partof the cylinder 174. This will urge the carriage C downwardly relativeto the frame F whereby first the cutter discs 30 and then the auxiliarywheels 32 and 33 will be engaged with the surface of the paved strip;continued downward movement of the carriage after the cutter discsengage this surface, but before the auxiliary wheels engage it, causingthe discs to cut through the strip to the depth of the kcrf. Once thcauxiliary wheels do engage the paved strip, the frame F will riserelative to the carriage so as to-lift the wheels W clear of the pavedstrip, as shown in Figure 5. Next, the entire assembly will be drivenacross the paved strip to the left by the auxiliary wheels 32, asindicated by the directional arrow in Figure 16. During this movementthe cutter discs will form a transversely extending kerf across thepaved strip.

When the assembly has reached the left end of its travel, as indicatedby the dotted outline in Figure 16, the operator will move the operatinghandle 191 of the main controller valve so as to release hydraulic fluidfrom the lower end of cylinder 174 and admit it to the upper endthereof. This will serve to lower the frame F until its wheels are againengaged with the surface of the paved strip, at which time the carriageC will bc raised off the surface to its original position. The frame Fmay then be driven along the paved strip under the influence of thefront wheels 44 to the next point at which a kerf is to be cut. Duringsuch movement the operator may control the course followed by the frameby means of the steering mechanism 76.

It should be especially observed that the apparatus embodying thepresentapparatus is provided with means for conserving the amount offuel consumed by the internal combustion engines 92 and 94. Thus,referring to Figure 8, such means includes a cam lever 175 shown`pivotally mounted by cach of the supports for such engines. The lowerend of each of these cam levers carry a roller 177, while the upper endsthereof are connected to the throttles (not shown) of the respectiveengines. It is anticipated that during the time the carriage C is in itsraised position of Figures 1, 2, 6 and 9, the rollers 177 will ride uponthe sides of the frame elements 36. At this time the engine throttleswill be set in an idling position. When the carriage is lowered into itspavement cutting position of Figure 5, however, the rollers 177 roll oilthe frame elements 36 and the upper ends of the levers move the enginethrottles to an advanced position. With this arrangement, the engineswill be permitted to idle when the carriage is in a raised position andwill only develop appreciable power during the actual cutting of thepavement.

Operation of the hydraulic system of Figures 11 through 16 In theoperation of the hydraulic system shown` in Figures 11 through 16,assuming the carriage to be disposed in its upper position of Figures l,2, and 6, the control lever 191 of the main controller valve 190 willinitially be in a neutral position so that fluid from the pump 176 willpass through conduit 188 into the main controller valve and return bymeans of conduit 194 to the top of the reservoir 184. If the lever 191is then `moved to its first position, fluid flow through the returnconduit 194 will be cut ofl and the fluid from the pump 176 will insteadbe directed through conduit 192 into the bottom of cylinder 174. Thiswill cause the cylinder 174 to be moved downwardly relative to thepiston 123 thereby urging the carriage downwardly relative to the frame.,During .such .moi/ement, -iiuid Y,trapped ubetween the topof the pistonl73.and,the.upperend wofthe cylinder 174 must pass through fthe `top.restrictor valve 210. The setting of this restrictor .valve should be`suchthat the proper rate of iluid flow out .of the upper end of the Ycylinder will be obtained to provide the desired rate of cylindertravel. The 'fluid passing `outof Athe upper end of the cylinder willowby .means of conduits 202 into one side of the throttling valve 1.98 andr'by means of conduit 196 from the `other side of the throttling valveto the main controller .valve .1.90. The fluid entering the latter valvewillthen lpass through return conduit 194 to the reservoir 184.

As the carriagemoves downwardly, the cam wheel 230 of the throttling.valve 198 will contact the ibeveled upper edge of the=cam plate 2534 asshow n in.Figure l2. This contact should take 1place @shortly -beforethe lower edges of the cutter discs 30 .engage the vsurface .of thepaved strip. Upon continued downward movement of the carriage the camwheel y230 will -roll downwardly over the cam plate untilit reaches itsretractedp ,ositionof Figures 13 and 14. At ythis time .-all flow ofhydraulic fluid through the throttling valve will be :blocked and theonly flow between conduits 202 and 196 must take place through theorifice valve .204. :Since this valve includes an orifice (not shown) ofcomparatively small diameter, the rate of ow between these Jconduits isreduced appreciably compared to the rate `of iiow therebetween whichtakes place when the throttling valve isopened. In this manner the rate`of vilow of iluid voutof the upper end of the cylinder 174, and, hencethespeed at which the carriage is being lowered, is reduced to ,adesired value. Accordingly, the speedat which the cutter discs may sawdownwardly into .the .pavement Ymay be ,closely c ontrolled. After thecutterdiscs have cut to v`the proper depth the auxiliary wheels 32 and,33 will engagethe surface of the paved strip 2S. At thistime .the camwheel 230 will have passed olf the lower edge of the cam plate 234whereby the throttling valve -1198 `willagainbe wide open. Accordingly,the frame F imay be moved upwardly at a high rate of speed.

When the frame F has been moved to its upper position of Figure 5, thecontrolflever 191 may be moved again to its neutral position.'I-he'rinwardilow of liquid through conduit 192 into the .lower Aendofthe cylinder -174 and the outward ow of liquid through conduit 202 and196 from the upper end of thecylinder will then be cut olf, and fluidentering the main.controll,er valve 190 through conduit 188 willbereturned toithe reservoir 184 by means of conduit 194. When it `isdesired to again lower the frame and raise the carriage, thetcontrollever 191 will be urged to its second position. In this position theflow of liquid through return conduit 194 will f-be cut olf and directedthrough conduit-196 into one-side of the throttling valve 198, and fromthe other-,side of rthis valve intothe upper end of the cylinder 114.Atithe same time the fluid in the cylinder below the piston 173 will befree to return through conduit 192 to the main controller valve 1% andreturn conduit 194 -to the reservoir 184. Thus, the cylinder will beurged upwardly relative to the piston 173, and the frame vwill in turnbelowered relative to the carriage until its wheels 44and 7.4 are againengaged with the surface of :thepaved Vstrip. At this time the framewill stop its downward :movement and the carriage will be liftedupwardly .until :it reaches its original position of Figures 1, 2 and'6.

It should be particularly noted that even though the 4throttling valve198 will vvbe'closed `'by contact of the cam wheel 234i withthe camAplate 234 during this-latter movement of the frame and carriage to theiroriginal positions, the speed at which the 'frame is 'lowered and thecarriage is lifted is not affected. This is true because of thepositioning of the check lvalve 206 between the conduits 1,96 and 202,which check valve bypasses both the throttling .valve 198 and theorifce-va1ve.2.0.4. -With-this arrange- .check valve 206 Vwill open soasvto bypass iluid between conduits 196 and 202. The capacity of thischeck valve should be substantially that of .the vopened throttlingvalve 198. It should be further noted that the rate at which thecylinder 174 moves relative to the piston 173 is controlled by thesetting of the restrictor valves 208 and 210. In this regard, thesetting of the two restrictor valves may be so adjusted as toprovidesubstantially the same rate of cylinder speed despitethedifference in internal volume between the upper and lower ends of thecylinder; this diference in volume resulting from the lpresence of thelower portion of the rod 172 in the upper end of the cylinder.

General arrangement of the apparatus shown in F gures 17 through 23 InFigures 17 through 23 thereis shown an alternate embodiment of thepresent invention. The apparatus of this alternate embodiment broadlycomprises a frame F having wheels 240 and 242 supporting it forlongitudinal movement along a paved strip ,28; a carriage C rotatablymounting a plurality of transversely spaced cutter discs 30, whichydiscs are normally supported above the surface of the paved strip 28 asshown in Figure 17; power actuated means H for etecting vertical:movement of the carriage C relative to the frame F; and power means Pfor etfecting horizontal movement of the carriage C relative to theframe F. In the operation of this apparatus, the frame F is moved alongthe paved strip in a longitudinal direction, stopping at longitudinallyspaced points thereon where a slot orkerf F is to be sawed or cuttherein. When the longitudinal movement of the frame has been halted,the power actuated means H moves the carriage C' downwardly so as topermit the cutter discs 30 to cut into the paved strip 28 the-depth ofthe desired kerf K, as shown in Figures 18 and 19. Next, the power meansP willmoveithe carriage C' horizontally relative to the frame Fin atransverse direction relative to the paved strip 28. During suchhorizontal movement a transversely extending kerf will be cut in thepaved strip by the cutter discs 3,0.

The frame F More particularly, the frame F will preferably include apair of side elements 244 rigidly interconnected at their front andrearends. Depending from the front and .the front portion of the frame,which engine is adapted to drive the front wheels 240, as well as toeffect rotation .of the cutter discs 30. The engine V246 drives thefront wheels 249 through a belt-,connected pulley train 247 and atransmission 243. An operators seat 249 is mounted at the rear of theframe F' adjacent a steering wheel mechanism 25@ connected by suitablemeans to the rear wheels whereby the latter may be steered by anoperator disposed upon vthe seat. Forwardly ofthe steering wheelmechanism 250 there are mounted within a housing 252, an engine (notshown), ya pump (not shown), and a hydraulic storage `chamber 254. Theengine rotates the pump whereby it may supply hydraulic Huid underpressure to the storage chamber 254.

The carriage C The carriage C includes an elongated boom 256 havinghorizontal ilanges 258 formed along its upper end and horizontal flanges261i `formed along V its lower end. The upper anges 258 are slidablyvcarried by a pair of support members 262.and 264, which support memberseach mount the lower end of a pair `of upstanding rods 266 and 268.These rods are coucentrically disposed within a vpair of verticalcylinders `270 and '272, respectively,

arsaof? secured to the side elements 244 of the frame F. The upper endsof the rods 266 and 268 are formed with collars 274 adapted to abut theupper edges of the cylinders 270 and 272 so as to limit the downwardmovement of the rods, and hence of the support members 262 and of theboom 256. An adjustment bolt 276 is provided for varying the verticalposition of each collar 27d relative to the rods 266 and 263 whereby thedepth of the kerf K may be adjusted.

Rigidly secured to the rear of the boom 2556 by brackets 278 is agenerally rectangular housing 23' .vherein disposed the cutter discs 30.The cutter ydiscs are each keyed to horizontal shafts shown rotatablyjournaled within strap-type bearings 282 rigidly connected at theirupper ends to the lower flanges 269 of the boom Cfu-6. The cutter discshafts are adapted to be rotated by n c engine 246, to which end theshafts mount pulleys 23d, permitting them to be interconnected by beltsAdditionally, the innermost pair of shafts mount a pair of pulleys 288which are shown connected by a pair of belts 290 to a pair of pulleys292. The latter pair of pulleys 292 are keyed to the rear end of a shaft.Z9/ mounted at the upper mid-portion of the carriage, which shaft isconnected at its front end to the rear end of a transfer shaft 295. Thefront end of this transfer shaft is coupled to the lower end of thepulley train 247. it will be noted that the connection of the transfershaft to the shaft 294 and to the pulley train 247 is by means ofuniversal joints U. This arrangement permits the cutter discs to berotated regardless of the position of the carriage C relative to theframe F. It will be understood that the shaft 295 is extensible tocompensate for movements of the carriage relative to the frame.

Referring to Figures 22 and 23, each of the support members 262 and 264iinclude a bifurcated base element 296 which pivotally mounts a sliderelement 297 at its lower central portion. A pair of leveling bolts 293are interposed between the front and rear ends of these two elements, asshown in Figure 23. As will be clear from Figure 22, the actualinterconnection of the base and slider elements is by means of a tube299 which encompasses a coaxial pin 306; the center of the tube beingpivotally supported between the bifurcations of the base element, andthe ends of the pin being rigidly aihxed to the upper portion of theslider element.

The power-actuated means H The power-actuated means H for eiectingvertical movement of the carriage relative to the frame F includes ahydraulic cylinder and plunger combination; the cylinder of which ispivotally secured to the frame at its rear end, and free end of theplunger of which is pivotally connected to a crank arm 302. The otherend of the crank arm 392 is rigidly secured to a horizontal pivot rod394 shown journaled within a pair of hangers 366, which hangers aresecured to the frame F. The opposite ends of the pivot rod 304 rigidlymount a pair of links 308 outwardly of the hangers 306. The free end ofeach link is pivotally connected to the upper end of a tie rod 310; thelower ends of the tie rods being pivotally secured to a bracket 312formed on support members 262 and 264. With this arrangement, verticalmovement of the support members and hence of the carriage may beeffected by the introduction of hydraulic iiuid into the cylin der andplunger combination, the cylinder of which is connected to the hydraulicstorage chamber 254 by conduits 314.

The power means P The power-actuated means P for effecting horizontalmovement of the carriage C relative to the frame F includes a hydrauliccylinder 316, which, as clearly shown in .Figures 19 and 21, ispivotally connected at one of its ends between a pair of lugs 318secured upon acrosspiece of the frame F. Reciprocally disposed withinthis cylinder is a piston 320 which rigidly mounts a rod 322 shownextending from the opposite side of the cylinder. Conduits 324 and 326connect the opposite ends of the cylinder with the hydraulic storagechamber 254. A control valve 327 disposed adjacent the operators seat249 is adapted to effect the introduction of hydraulic iiuid at eitherend of the cylinder 316 whereby the piston 320 and hence rod 322 may beurged in either direction. The free end of the rod 322 is bifurcated,and a pin 328 extending between the bifurcations serves to pivotallyconnect the rod and the upper end of a swing lever 33t). The mid-portionof this swing lever 330 mounts a pin 332 shown journaled between a pairof strap-type bearings 334 which are bolted to a bracket 336 rigidlyattached to one side of the frame F. The lower end of the swing lever33t) is pivotally connected to one end of a crossrcd 338; the oppositeend of this cross-rod being pivotally connected to a box 340 mounted bythe mid-portion of the carriage. With this arrangement, the introductionof hydraulic fluid into the opposite ends of the cylinder 316 will causethe swing lever 330 to pivot about its pin 332, thereby effectingconcurrent horizontal movement of the cross-rod 338 relative to theframe. Since the cross rod is connected to the box 340, the entirecarriage C' will likewise be moved horizontally relative to the frame.

Arrangement for supplying coolant to the cutter discs In order to supplythe cutter discs 30 with a coolant during the pavement cuttingoperation, a plurality of nozzles 342 are provided. Referring to Figure20, each nozzle 342 includes a pair of horizontally spaced pipes 344between which rotate one of the cutter discs. The pipes are each formedwith small apertures adjacent the cutter disc adapted to spray coolantthereon. The pipes 344. are mounted by a hollow member 346 which is inturn secured to the lower end of a vertical conduit 348. The upper endof each conduit 348 is connected by means of a hose 350 to a horizontalcommon conduit 352. This common conduit receives coolant from a tank 354disposed between the front portion of the frame members 4244 by means ofa hose 356. A control valve 35S mounted on the frame F is adapted tocontrol the flow of coolant from the tank into the common conduit 352.This control valve 358 will preferably be arranged to admit coolant tothe common conduit only when the cutter discs 3i) are performing theactual sawing operation. To this end, a cable 360 may connect the handle361 of the control valve with the carriage box 34). This handle 361 isnormally spring-loaded to an upper or closed position when the carriageC' is in its raised position. The handle 361 may be pulled downwardly bythe cable 360 when the carriage is lowered so as to open the controlvalve 358. It has been found desirable to have the cable 360 of such alength that the control valve 353 1s opened when the lower edges of thecutter discs are disposed about one inch above the surface of the pavedstrip.

Operation of the apparatus shown in Figures 17 throng/z 23 In operation,the apparatus is driven along the paved strip 28 with the carriage C inits raised position of Figure 17 to the point Where the kerf K is to beformed. Referring to Figure 19, assuming the kerl' is to be formed fromleft-to-right in this view, the left cutter disc will be spotted overthe left side of the paved strip with the carriage being disposed atright angles to the strip. When the apparatus has been properly spotted,the operator may actuate the cylinder and plunger combination 360 so asto lower the carriage C to its position of Figures 18 and 19; the cutterdiscs sawing into the pavement to the proper depth of the kerf. Next,again referring to Figure 19, hydraulic fluid will be admitted to theright end of the cylinder 316 so as to cause the piston 320 and rod 322to move to the left. The lower end of the vswingr lever 330 will therebybe swung to theright, etfectving concurrent movementof the carriage tothe right. -In this manner a transversely extending kerf will lbe -cutacross the paved strip. When the carriage has been moved the necessarydistance to the right, kit may be again ,raised and then movedhorizontally back to its original position. The frame F may then bedriven vto the next point at which a kerf is to be cut, and theabove-described ,process repeated.

It lshould be especially observed that as in the case of vthe apparatusof Figures 1 through 17, the alternate apparatus is equipped with meansfor conserving engine fuel when the carriage C is in a raised position.Referring to rvFigure 19, such means includes Va cam lever 371 which is-shown pivotally connected to the side of the frame F.

The lower end of this cam lever carries a roller 373 which rides on thesurface 375 of the support member 262 when .the carriage is in itsraised position. When vthe carriage is lowered into its pavement cuttingposition, however, the roller 373 will ride ofr this surface. The upperend of the cam lever 371 `is connected to the throttle (not shown) ofthe engine `246. It is anticipated that during the time the carriage isin'its raised position, the upper end of the cam lever will maintain theengine throttle lin an idling position. When, however, the carriage islowered and the roller 373 rolls otf the surface 375, the upper end ofthe cam lever will move the engine throttle to .an advanced position.When the motor 246 is con- 4nected for driving the device a handthrottle independent of the action of the cam lever, maybe employed toaccelerate the engine speed.

Cutting diagonal kerfs with the apparatus of Figures 1 through I6 Undercertain conditions it is desirable vthat roadways be formed with kerfswhich extend diagonally relative to :the side edges of the roadwayrather than at right angles thereto. The use of such diagonally cutkerfs reduces the impact imposed upon the individual roadway sectionssince .only one front wheel and `one rear wheel of a motor vehiclepassing over the roadway will hit a section at one time.

Both the preferred form of apparatus shown in Figures 1 through 16 andthe alternate form of apparatus shown in Figures 17 through 23 arecapable of cutting diagonal kerfs. Thus, referring to Figure 7, asstated previously hereinbefore, the subframe 40 is v`pivotable about avertical Vaxis relative to the main frame F. To this end, vthefsides ofthe rear upper portions of the subframe 40 and the sides of the frontportion of the frame F rigidly mount apair of complementary arcuateadjustment plates 364 and 366. The frame adjustment plates 366 areformed with slots 368 wherein are received upstanding bolts 370 havingtheir lower ends rigidly affixed ,to the top o1' the subframesadjustment plates 364. Nuts 372 are provided for the upper ends of thebolts 370. With this arrangement, as indicated bythe `arrows in Figure7, the angle of the subframe 40 and hence ofthe front wheels 44, maybeadjustablyvaried relative to the frame by loosening the nuts 372,pivoting the subframe through the desired number of degrees (the bolts370 sliding in vthe slots 368 during such movement), and then re-.tightening the nuts 372.

In cutting a diagonal kerf, the operation isessentially similar to thatfollowed in :cutting a right-angled kerf. In this regard it should benoted that once the angularity of the front wheels 44 has been properlyadjusted, all the operator must do in order to set the cutter discs atthe correct angle relative to the roadway is tospot the frame F at thepoint where the kerf is to be formed with the axes of the front wheels44 at aright angle tothe side edge of the roadway. The pointer 246 maybe utilized in this procedure. With the front wheels so positioned, thecarriage C will automatically be disposed at the desired diagonal anglerelative to the side edges of :to change.

the roadway. Thereafter, the l,carriage Cfmay :belowered `so astoengagethe cutter discs 30 and the auxiliary wheels 3.2ar1d33rand thekerfmaybe .cut in the manner described Yin full hereinbefore.

lt should be especiallynoted vthatboth 0f the aforedescribed forms ofpavement vcutting yapparatus provide Along cutter vdisc wear. Such long`wear primarily results fromthe short distance each ydisc must travelduring the cutting of a kerf. .In this regard, where a kerf twelve feetlong .must vbe cut, a carriage mountingeight cutter discs oneighteen-inch centers may be utilized. With this arrangement, thecarriage, and hence each cutter disc,

,needionly be moved a distance of eighteen inches during the .cutting ofa kerf. Because o fthis short length .of cutter disc travel, each discwill remain comparatively cool during each cutting operation. After eachindividual kerf has been cut, the cutter discs areaiorded an opportunityto cool as Ythe frame is driven to the next point at which a kerf is tobezformed.

While there has been shown what is .at present believed to be thepreferred embodiment and an Valternate embodiment of the presentinvention, itwill .be ,apparent to those skilled ,in the art thatvarious modifications and changes may be made thereto. For example, thenumber `of .Cutter discs aswell as .the spacing thereof, may be variedin accordance with ...the optimumconditions of a `particular job.Additionally, the exact ynumber of wheels utilized for supporting theframe or lthe carriage lis subject These and other such .modificationsand changes, however, are included in the spirit of the inven- .tion.and the scope of the appended claims.

l :claim:

.l. vA mobile pavement cutting apparatus for sawing spaced weakenedplane joint kerfs transversely of an relongate roadway pavingstrip,comprising: a -vehicle includng a frame, means forsupporting saidvehicle for `movement .longitudinally along said strip yto and 4fromselected plane joint locations, a saw carriage support,

`means for vmounting said support gfrom said `frame for verticalmovement'relative thereto, a saw carriage, means mounting said carriagevfrom said support for lhorizontal movement relative thereto, aplurality of `saws mounted by said carriage in a common plane transverseof the Y direction of travel of said vehicle when moving longitudinallyof said strip and parallel to the direction of horizontal motion of saidcarriage, means interconnecting said frame and saw carriage support-forybodily moving said carriage and saws vertically with respect to saidframe to engage and disengage said saws with respect .to said strip,means interconnecting said frame and carriage for bodily moving said sawcarriage and saws horizontally with respect to `said frame whereby saidsaws may perform a transverse kerf cutting operation while engaged withsaid strip and means for rotating said saws While engaging said stripand moving transverselythereof.

2. Cutting apparatus as set forth in claim l including; power-operatedmeans for rotating said saws and means responsive to the relativevertical position of said frame and said carriage for controlling thespeed of said poweroperated means.

3. Cutting apparatus as set forth in claim l including an internalcombustion engine for rotating said saws, throttle means for controllingthe speed of said engine and means interposed between said frame andsaid car- .riage` and responsive to the relative vertical positionthereof for automatically advancing said throttle means as said saws aremoved toward said strip.

4. Cutting apparatus as set forth in claim l including lan internalcombustion engine `for rotating said saws, throttle means forcontrolling the speed of said engine, said throttle means normally beingdisposed in an idling position and means interposed between said lframeand said carriage and responsive to the relative vertical positionthereof for automatically advancing said throttle means as said saws aremoved toward said strip.

5. Cutting apparatus as set forth in claim l including means forsupplying a coolant to said saws including a valve and means responsiveto the relative vertical position of said frame and said carriage forcontrolling the degree of opening of said valve.

6. Cutting apparatus as set forth in claim 1 including means forsupplying a coolant to said saws including a normally closed valve andmeans interposed between said frame and said carriage and responsive tothe relative vertical position thereof for automatically opening saidvalve.

7. Cutting apparatus as set forth in claim 1 including a nozzle for eachof said saws, a main conduit connected to each of said nozzles `forsupplying a coolant thereto, a source of coolant, a control valve, saidcontrol valve being biased to a closed position when said carriage is inan elevated position, and means connecting said control valve to saidcarriage adapted to urge said control valve to an open position whensaid carriage is lowered.

8. Cutting apparatus as set forth in claim l including an engine forrotating said saws, throttle means for controlling the speed of saidengine, means for supplying a coolant to said saws including a valve,means interposed between said frame and said carriage responsive to therelative vertical position thereof for automatically advancing saidthrottle means as said saws are moved toward said strip and meansinterposed between said frame and said carriage responsive to therelative vertical position thereof for controlling the degree oi'opening of said valve.

9. Cutting apparatus as set forth in claim l including an engine meansfor rotating said saws; throttle means for controlling the speed of saidengine, said throttle means being normally disposed in an idlingposition, means for supplying a coolant to said saws including anormally closed valve, means interposed between said frame and saidcarriage responsive to the relative vertical position thereof forautomatically advancing said throttle means as said saws are movedtoward said strip and means interposed between said frame and saidcarriage means responsive to the relative vertical position thereof foropening said valve as said saws are moved towards said strip.

l0. A mobile pavement cutting apparatus for sawing spaced weakened planejoint kerfs transversely of an elongate roadway paving strip,comprising: a vehicle including a frame, means for supporting saidvehicle for movement longitudinally along said strip to and fromselected plane joint locations, a source of motive power mounted on saidframe, a saw carriage support, means for mounting said support from saidframe for vertical 4movement relative thereto, a saw carriage, meansmounting said carriage from said support for horizontal movementrelative thereto. a plurality of saws mounted by said carriage in acommon plane transverse of the direction of travel of said vehicle whenmoving longitudinally of said strip and parallel to the direction ofhorizontal motion ot said carriage, means interconnecting said trame andsaw carriage support for bodily moving said carriage and saws verticallywith respect to said frame to engage and disengage said saws withrespect to said strip,` a driving connection between said source ofmotive Ipower and said means for moving said carriage and sawsvertically,

means interconnecting said .frame and carriage for bodily 16 said stripfor supporting said vehicle for movement longitudinally along said stripto and from selected plane joint locations, a saw carriage support,means for mounting said support from said frame for vertical movementrelative thereto, a saw carriage, means mounting said carriage from said support for horizontal movement relative thereto, a plurality ofsaws mounted by said carriage in a common plane transverse of thedirection of travel `of said vehicle when moving longitudinally of saidstrip and parallel to the direction of horizontal motion of saidcarriage, means inter-connecting said trame and saw carriage support forbodily moving said carriage and saws vertically with respect to saidframe to engage and disengage said saws with respect to said strip,means interconnecting said frame and carriage for bodily moving said sawcarriage and saws horizontally with respect to said frame whereby saidsaws may perform a transverse kert cutting operation while engaged withsaid strip and means for rotating said saws while engaging said stripand moving transversely thereof.

l2. A mobile pavement cutting apparatus for sawing spaced weakened planejoint kerfs transversely of an elongate roadway paving strip,comprising: a vehicle in' cluding a frame, wheels mounted on axesnormally transerse of said strip for supporting said vehicle `formovement longitudinally along said strip to and from selected planejoint locations, means for steering said wheels so that the vehicletravel may be independent of said strip a saw carriage support, meansfor mounting said support from said frame for vertical movement relativethereto, a saw carriage, means mounting said carriage from said supportfor horizontal movement relative thereto, a plurality of saws mounted insaid carriage in a common plane transverse of the direction of travel ofsaid vehicle when moving longitudinally of said strip and parallel tothe direction of horizontal motion of said carriage meansinterconnectingsaid frame and saw carriage support for 'bodily movingsaid carriage and saws vertically with respect to said frame to engageand disengage said saws with respect to said strip, meansinterconnecting said frame and carriage for bodily moving said sawcarriage and saws horizontally with respect to said frame whereby saidsaws may perform a transverse lterf cutting operation while engaged withsaid strip and means for rotating said saws while engaging said stripand moving transversely thereof.

13. A mobile pavement cutting apparatus for sawing spaced weakened planejoint kerfs transversely of an elongate roadway paving strip,comprising: a vehicle including a frame, wheels mounted on axes normallytransverse of said strip for supporting said vehicle for movementlongitudinally along said strip to and from selected plane jointlocations, a source of motive power mounted on saidframe, a saw carriagesupport, means for mounting said support from said frame for verticalmovement relative thereto, a saw carriage, means mounting said carriagefrom said support for horizontal movement relative thereto, a pluralityof saws mounted by said carriage in a common plane transverse of thedirection of travel of said vehicle when moving longitudinally of saidstrip and parallel to the direction of horizontal motion of saidcarriage, means interconnecting said 'frame and saw carriage support forbodily moving said carriage and saws, vertically with respect to saidframe to engage and discngage said saws with respect to said strip, adriving connection between said source of motive power and said meansfor moving said carriage vertically, means interconnecting said frameand carriage for bodily moving said saw carriage and saws horizontallywith respect to said frame whereby said saws may perform a transversekerf cutting operation while engaged with said strip, a drivingconnection between said source of motive power and said means for movingsaid carriage horizontally and means for rotating said saws whileengaging said strip and moving transversely thereof.

14. A mobile pavement cutting Aapparatus for sawing spaced `weakenedplane joint kerfs transversely of an elongate roadway paving strip,comprising: a vehicle including a frame, wheels mounted on axes normallytransverse of said strip for supporting said vehicle for movementlongitudinally along said strip to and from selected plane jointlocations, means for steering Isaid wheels so that the vehicle travelmay be independent of said strip, a source of motive power mounted onsaid frame, a saw carriage support, means for mounting said support fromsaid frame for vertical movement relative thereto, a saw carriage, meansmounting said carriage from said support for horizontal movementrelative thereto, a plurality of saws mounted by said carriage in acommon plane transverse of the direction of travel of said vehicle whenmoving longitudinally of said strip and parallel to the direction ofhorizontal motion of said carriage, means interconnecting said frame andsaw carriage support for bodily moving said carriage and saws verticallywith respect to said frame to engage and disengage said saws withrespect to said strip, a driving connection between said source ofmotive power and said means for moving said carriage vertically, meansinterconnecting said frame and carriage for bodily moving said sawcarriage and saws horizontally with respect to said frame whereby saidsaws may perform a transverse kerf cutting operation while engaged withsaid strip, a driving connection between said source of motive power andsaid means for moving said carriage horizontally and means for rotatingsaid saws while engaging said strip and moving transversely thereof.

15. A mobile pavement cutting apparatus for sawing spaced weakened planejoint kerfs transversely of an elongate roadway paving strip,comprising: a vehicle including a frame, wheels mounted on axes normallytransverse of Isaid strip for supporting said vehicle for movementlongitudinally along said strip to and from selected plane jointlocations, means for steering said wheels so that the vehicle travel maybe independent of said strip, a source of motive power mounted on saidframe, a saw carriage support, means for mounting said support from saidframe for vertical movement relative thereto, a saw carriage, meansmounting said carriage from said support for horizontal movementrelative thereto, a plurality of saws mounted by said carriage in asingle plane transverse of the direction of travel of said vehicle whenmoving longitudinally of said strip and parallel to the direction ofhorizontal motion of said carriage, means interconnecting said frame andsaw carriage support for bodily moving said carriage and saws verticallywith respect to said frame to engage and disengage said saws withrespect to said strip, a driving connection between said source ofmotive power and said means for moving said carriage vertically, meansinterconnecting said frame and carriage for bodily moving said sawcarriage and saws horizontally with respect to said frame whereby saidsaws may perform a transverse kerf cuttingoperation while engaged withsaid strip, a driving connection between said source of motive power andsaid means for moving said carriage horizontally and means for rotatingsaid saws While engaging said strip and moving transversely thereof.

References Cited in the le of this patent UNITED STATES PATENTS 659,867Hetherington Oct. 16, 1900 689,064 Butler et al. Dec. 17, 1901 909,059Card Jan. 5, 1909 1,071,776 Morrissey Sept. 2, 1913 1,096,860 Quick May19, 1914 1,302,917 Hairgrove May 6, 1919 1,441,311 Trowbridge Jan. 9,1923 1,662,473 Ralston Mar. 13, 1928 1,733,062 Hove Oct. 22, 19291,738,646 Graves Dec. 10, 1929 2,195,108 Graff Mar. 26, 1940 2,311,891Tyson Feb. 23, 1943 2,364,879 Talboys Dec. 12, 1944 2,365,267 HememannDec. 19, 1944 2,438,159 Faber Mar. 23, 1948 2,502,043 Howard Mar. 28,1950 2,506,076 Garrison May 2, 1950 2,569,682 Lewis Oct. 2, 19512,657,596 l De Armas Nov. 3, 1953

